Air circuit breakers as described within U.S. Pat. No. 3,095,489 entitled "Manual Charging Means for Stored Energy Closing Mechanisms of Electric Circuit Breakers" and U.S. Pat. No. 3,084,238 entitled "Ratchet Mechanism for Charging a Closing Spring in an Electric Circuit Breaker" include operating mechanisms that are mainly exposed to the environment. Since the air circuit breakers are rated to carry several thousand amperes of current continuously, the exposure to convection cooling air assists in keeping the operating components within reasonable temperature limits.
Such air circuit breakers are usually provided with a motor operator such as described in U.S. Pat. No. 4,167,988 entitled "Ratcheting Mechanism for Circuit Breaker Motor Operator" or a manual handle as described in U.S. Pat. No. 3,729,065 entitled "Means for Charging A Stored Energy Circuit Breaker Closing Device" for charging the powerful closing springs contained within the air circuit breaker operating mechanism.
When the circuit breaker closing springs are brought to their fully-charged conditions, it is important that the springs do not become inadvertently discharged while an operator has hold of the charging handle in order to avoid damage to the ratchet mechanism and the associated air circuit breaker contacts. An early arrangement of a latching means to prevent rotation of a closing springs charging handle is found in U.S. Pat. No. 4,475,021 entitled "Air Circuit Breaker".
When the circuit breaker closing springs are completely charged, the holding pawl is removed from the charging gear to allow the charging shaft to rotate in the reverse direction when the circuit breaker closing button is activated, as described in U.S. Pat. No. 5,883,351 entitled "Ratcheting Mechanism for Industrial-Rated Circuit Breaker" filed on May 27, 1997.
One arrangement for releasing charged circuit breaker closing springs to close the circuit breaker contacts is found in U.S. patent application Ser. No. 08/864,165 entitled "Closing Springs Release Mechanism for industrial-Rated Circuit Breaker" filed on May 28, 1997.
Two separate arrangements for interlocking the circuit breaker closing button to prevent release of the circuit breaker closing springs to forestall closing the circuit breaker contacts are described within U.S. Pat. No. 5,889,250 entitled "Circuit Breaker Closing Springs Button Interlock Mechanism" filed on Jun. 19, 1997 and U.S. patent application Ser. No. 08/878,594 entitled "Push-button Interlock Mechanism for an Industrial-Rated Circuit Breaker" filed on Jun. 19, 1997.
In some situations, when remote circuit breaker accessory devices are employed, it is necessary to release the circuit breaker interlock to allow the circuit breaker closing spring to close the circuit breaker contacts. However, it is also required to allow the closing spring to become charged so that the contacts can be immediately re-closed following an overcurrent occurrence. To allow a remotely-operated accessory to release the circuit breaker closing spring when the contacts have already closed could result in damage both to the circuit breaker contacts as well as to the components within the circuit breaker closing spring assembly, per se.
One purpose of the invention is to provide a lock-out arrangement whereby the circuit breaker closing spring can be released to close the circuit breaker contacts from the OPEN to CLOSED condition when the circuit breaker contacts are separated and whereby the circuit breaker closing spring is prevented from becoming released after the circuit breaker contacts have closed.